Method for detecting flaws in tubular steel castings



' Jan. 27, i948. E. G. FoRssELL 2,435,134

ME'1HOD FOR DETECTING FLAWS IN TUBULAR STEEL CASTINGS FiledA Sept. 18, 1944 2 Sheets-Sheet Vl Jan. 27, 1948. E, G, FQRSSELL 2,435,134

METHOD FOR DETECTING FLAWS IN TUBULAR STEEL CASTINGS Filed Sept. 18, 1944 2 Sheets-Sheet 2 www@ Patented Jan. 27, 1948 METHOD FORKDETEGTG'YFLAWS IN TUBULAR STEEL CASTINGSy ric G. Forssell, Kenmore, NL Y., assigner to W. I.

H. Miner, Inc., Chicag Delaware o, Ill., av corporation of Application September 18, 1944, Serial No. 554,593

(Cl. 250g-53) 2 Claims.

, 'rhis invention relates toL improvements in Method for detecting flaws in steel castings, and more particularly steel castings of tubular shape.

Various methods and means have been employed in foundry practice for detecting flaws in steel castings, including the examination of the castings through the` use of X-rays by photographing on a sensitized film, the developed photographic lfn presenting a Visual reproduction of the texture of the metal, thereby giving a graphic; picture of the condition of the castings, which clearly indicates any flaws which may exist. This X-'ray photography of castings is generally known in this art as X-radiographing. Y

The main object of my invention is to provide a reliable method of detecting flaws in tubular steel castings by X-ray photographing, on a continuous lm, extensive portions of the casting, thereby providing a single continuous picture of the entire area under consideration.

A further object of the invention is to provide simple and eiiicient means for carrying out the method set forth in the preceding paragraph.

Another object of the invention is to provide a method of Xeradiographing tubular steel caste ings comprising the following procedure. Mounting a continuous nlm within the tubular steel casting member in close proximity to the interior surface of the sidewalls thereof and extending entirely around thel tubular member, rotating the tubular member and the film in unison therewith about the central longitudinal axis of said meinber, and exposing said tubular member to the effect of the rays of an X-ray apparatus, thereby progressively exposing successive portions of the Vtubular member to the source of said rays.

A still further object of the invention is to pros vide an apparatus for carrying out the method 'as set forth in the preceding paragraph comprising a rotary table or chuck on which the tubular steel casting is secured for rotation therewith, a source of Xer'ays' radial to the axis of rotation of the table and tubular member, a photographic nlm holder telescoped within the tubular meme bei" for holding a continuous lm in close proximity to the inner yface of the annular side wall of the member, and a lead screen between the tubular member and the source of X-rays, the screen having a lengthwise extending, narrow opening therethrough, permitting the free passage ofthe X-rays, thereby conning the action lo f the eiectiv rays to elongated, relatively nar- 'rowY Held, and 'means for rotating the table and 'member thereof while exposed to the effect of the X-rays as permitted by said screen.

Still another object of thelinventionis to prosv vide means in an apparatus as set forth in theipreceding paragraph,for'e'iectively screening the nlm adjacent the-'wailiof the tubularmemberopposite to the wallVv portion being subjected to the eiect of the X-rays.

Other objects of the? invention will more clearly appear from: the description and claims hereinafter following.

In the drawings forming -a part of thisspecitl cation, Figure 1 is a side-elevational view of thel improvedv apparatus or mechanism employed in carrying out my improved method. Figure 2 is a top plan view of Figure 1. Figure 3ds a front end elevational View of Figure 1, looking. from lei-t to right in said figure.. the Iii-fray apparatus which is the source of the Xexays employed in connection with my improved method and apparatus being illustrated diagrammatically in this View. Figure 4 is a longitudinal. vertical sectional view, corresponding tothe line 4-4 of Figure 3 of the tubular member and the holder contained therein', the table' or chuck ofthe apparatus being broken away and other parts .of the mechanism being omitted. Figure 5 is a transverse, vertical sectional view, corresponding. substantially tothe line 5-5` of Figure 4.

As shown in the drawings, my improved ap.- paratus by whichV the improvedA method is carried out comprises broadly a supporting frame A; a lrotary tab-1e or chuck B; a screen C; a hinged supporting table D" ,tor the screen; a film holder E; retaining means Fior clamping the nlm holder Within the Vtubular steel casting.; clamps Cire-Gf for nxing the casting Aon the rotary table .'B; and. an X-ray apparatus y Y The supporting 'frame A lcomprises a horizontal, platform Lf-the iront end of which only is -shown in the drawings. H'Ihe table l0 is provided with supportingfeet at its' corners, one of which is 'shown in Figure 1 and is indicated by yI I. The frame A has a supporting standard i2 carrying al bearing member t3' for a rotary shaft hereinafter referred to. The .frame is also' provided .with upstanding columns 'I4- 1.a at opposite sides of the NplatformHIL The columns I4-4 have forwardlfexteiiding arms l5'-I5 near the UDI-3er ends thereof. The arm-s l-el are sl'i'glitly'ina clined Lupwardly toward 'their outer ends. {Inclined bracing struts `IE---f-'Jlf extend from vthe Vouter edge of" the bade I'--to t'hearns' 15e-t5 and support --the latter; The bracing strutsV I' -it project slightly above the arms |,5-I5 and `said projecting jportionsjarelprovided with flat, horisupporting the table D. The columns I4-I4 project some distance above the level of the arms I5-I5, as clearly shown in Figures 1 and 3.

The rotary table or chuck B is in the form of a flat, disclike plate having a rearwardly extending axial sleeve vI8 formed integral therewith, adapted to receive the end of a shaft I9 which is xed thereto by being keyed or secured in any other suitable well-known manner. The disc or chuck B is preferably reenforced by a plurality of radial webs --20 formed integral with said disc and the sleeve I8. The shaft I9 is rotatably mounted in the bearing I3, thus supporting the table or chuck B for rotation about ahorizontal axis. The driving means for the shaft is not illustrated but lt is such that the shaft I9 is rotated at relatively slow speed, and the driving means may be in the form of an electric motor and any well-known type of reduction gearing interposed between and connecting the motor to the shaft AI9.

The rotary table B carries the clamps G-G, which are disposed at opposite sides of the center of rotation of the table and are in the form of hooks having straight shank portions 2 I2I extending through openings 22-22 in the table B. The shank portions 2I-2I are threaded at their outer ends to receive clamping nuts 23-23. At the opposite end, each clamp G has an angularly bent portion 24 substantially at right angles to the shank thereof forming the hook proper of the clamp.

The clamps G-G are especially designed to securely mount the particular type of tubular steel casting 25 herein illustrated, namely, the casing of a railway friction draft gear, of wellknown design, on the table B. As will be understood, other types of tubular members than the draft gear casting or casing 25 may be supported for rotation by the table B, the clamping means being suitably modied to suit conditions, the draft gear casing being merely illustrative of one type of steel casting which may be rotatively supported by the table. The well-known railway friction draft gear, of which the casing 25 forms a part, comprises briefly the casing 25 and a spring resisted friction clutch slidable in the casing, the casing 25, as illustrated, being of standard design.

The supporting table D comprises a rectangular open frame 26 having rearwardly extending, spaced side arms V2'I--21 oset laterally outwardly from the sides of the frame 26. The arms 2'I-2I at their rear ends embrace the outer sides of the columns I4- I4 and are hinged thereto at the upper ends thereof by a pivot rod 28 extending through suitable openings in said standards and arms. In the operative position of the screen supporting table D, the front ends of the arms 21--2l, that is, the ends thereof where'they join the frame 26, are adapted to rest on the supports formed by the flat abutment faces I'I--I1 at the upper ends of the struts I6-I5 to maintain the table in horizontal position above the tubular casting 25 and parallel to the axis of rotation of said casting. As will be seen upon reference to Figure 2, the `arms 21-21 are' spaced apart a sufiicient distance to clear the upper portion of the rotary table B when the table D is swung to its horizontal position, as shown` in Figures l, 2, and 3. I

The screen C, as illustrated, comprises two relativelyl thick, rectangular lead plates 251-29, which are clamped within the opening of the frame 26 of the table D. The lead plates 29, as

shown, are relatively long and are arranged in the frame 26 lengthwise of the axis of rotation of the draft gear casing or tubular steel casting 25, and are clamped within said frame by top and bottom clamping plates 30-30 arranged at opposite ends of said frame and secured thereto by bolts 3I-3I extending through said plates and through slots 32-32 in the transverse members of said frame. The clamping plates 30-30 overlap and embrace the lead plates at the top and bottom sides of the latter and are preferably secured thereto by bolts 33-33 extending through said clamping plates and the lead plates. The slots 32-32 provide for lateral adjustment of the lead plates 29-29 within the frame 26, suftlcient clearancer for this purpose being provided between the outer side edges of the plates 29-29 andthe side members of the frame 26. In the operative position thereof, the lead plates 29-29 are so adjusted that they are laterally spaced apart, as shown most clearly in Figure 2, to provide an opening 34 therebetween, extending lengthwise of the frame 26 and parallel to and in vertical alignment with the axis of rotation of the draft gear casing 25.

The X-ray apparatus employed in my improved method in connection with my improved apparatus may be of any well-known type, and is indicated by H, and as shown in Figure 3 is located above the screen C. The X-ray apparatus H is in vertical alignment with the axis of rotation of the draft gear casing 25 and the opening 34 of the screen C.

The film holder E comprises a plug 35 fitting within the open end of the casing 25. The standard friction gear casing 25 herein shown is of hexagonal, interior cross section providing six flat friction surfaces 36--36. The friction surfaces 36-35 converge inwardly of the casing, and the pluglike film holder Eis made of hexagonal transverse cross section and tapered to properly t the hexagonal opening of the casing. The plug 35 of the nlm holder E is preferably in the form of a lead block and has a laterally, outwardly extending, peripheral flange 31 at the outer end thereof adapted to bear on the front end of the casing 25, that is, it overlaps the end edge of the hexagonal side wall of the casing. The photographic film employed, which is in the form of a continuous strip 38, is wrapped around the hexagonal plug 35 and is covered by a thin tubular lead shell 39, which also may be in the form of a strip or sheet surrounding the film covered block 35. The film holder E including the lead shell or cover 39 and loaded with the film 38 closely fits the interior of the casing 25 and is clamped in position by the retaining means F.

The retaining means F comprises a bolt 40 extending through an axial opening 4I in the plug 35 and projecting beyond the front end of said block; a tubular sleeve 42 surrounding the projecting end of the bolt; a disclike washer 43 interposed between the inner end of the sleeve 42 and the flanged end of the plug 35; a retaining nut 44 on the outer end of the bolt; and a washer 45 interposed between the nut and the sleeve.

The bolt is headed at the rear end, as indicated at 41, and said headed end is anchored in an inwardly projecting hollow boss 43 provided on the standard friction draft gear casing 25. As will be evident, the nut 44 when tightened serves to hold the film holder E tightly within the casing As hereinbefore stated, the casing 25 to be X- rayed is mounted on the rotary table or chuck B, being held thereon by the retaining clamps G-G, the angularly bent portions 24-24 of which are hooked into diametrically opposite openings 4.9-49 of the standard casing 25.

In carrying out my improved method, the operation is as follows: The lm holder E with the film loaded therein is rst placed within the tubular steel casting 25 and secured in place by the clamping bolt 40. The casting 25 is then clamped on the rotary table B, while the hinged screen supporting table D is in position swung up out of the way to facilitate mounting the casting on the rotary table B. The screen supporting table is then swung down to its operative horizontal position above the casting, as shown in Figure 1, the slit or opening in the screen C having been adjusted to the proper predetermined width. Power is then applied to the driving shaft I9 to slowly rotate the same and the table B together with the casting 25 thereon. At the same time the electric current is supplied to the X-ray apparatus H, thereby exposing the casting 25 and the photographic film in the lm holder E to the rays emanating from the X-ray apparatus In this connection it is pointed out that the lead plug 35 of the film holder E properly screens that portion of the photographic film at the side of the lm holder opposite to that exposed to the source of X-rays during rotation of the tubular casting, thereby preventing marring of the exposure which otherwise might occur by diffused rays reaching this portion of the film.

From the preceding description taken in connection with the drawings, it will be evident that I have provided a simple and eiiicient method and means for producing X-ray photographic records showing the cross sectional, internal structure of the walls of tubular steel castings, thereby giving a graphic representation in the form of a map embracing the entire circumference of the tubular member, which reveals any defects which may exist in the casting. It will be further evident that the accuracy of the resulting X-ray photo-v graph is greatly increased through my improvements by confining the exposure of the casting to the rays emanating from the X-ray source to a relatively narrow, elongated eld lengthwise of the tubular member, parallel to its axis, by means of the slitted lead screen which iilters out diverging rays and by limiting the diffusion of the rays by means of the thin lead outer covering strip and the inner lead core of the lm holder.

I have herein shown and described what I now consider the preferred manner of carrying out my invention, but the same is merely illustrative and I contemplate all changes and modi'cations that come within the scope of the claims appended hereto.

I claim:

1. A method of producing X-ray photographs of tubular steel castings comprising the following procedure: Placing a photographic film on the inner side of substantially the entire circumferential side wall area of the tubular casting to be photographed in close proximity to said Wall, said film being coextensive with said wall area, screening the inner side of said entire lm from the effect of the X-rays, slowly rotating the tubular casting and film about its central longitudinal axis while exposed to a Xradiation from a xed source of X-rays exterior to said tubular casting, and screening the rays emanating from said source of X-rays to restrict the rays reaching said casting to an elongated narrow field.

2. A method of producing X-ray photographs of tubular steel castings comprising the following procedure: Placing a photographic lm on the inner side of substantially the entire circumferential side wall area of the tubular casting to be photographed with a thin lead screen interposed between the film and the inner surface of said wall area, said film being coextensive with said wall area, screening the entire inner side of said film against the effect of X-rays, slowly rotating the tubular casting and film about its central 1ongitudinal axis while exposed to X-radiation from a fixed source of X-rays exterior to said tubular casting, and screening the rays emanating from said source to restrict the rays reaching said casting to an elongated narrow eld extending lengthwise and parallel to said axis of rotation.

ERIC G. FORSSELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,563,362 Herradora Dec. 1, 1925 2,025,488 Yap Dec. 24, 1935 2,306,194 Swaisgood Dec. 22, 1944 2,340,923 Boucher Feb. 8, 1944 2,396,069 Zapp Mar. 5, 1946 OTHER REFERENCES Industrial X-ray Units, Pub. 7A700, General Electric X-Ray Corp. Copy received v in Patent Oilce on June 1.5, 1942. (Copy in Div. 54.) 

